E-Invoice Big Update – Change in Invoice Number Format

E-Invoice Update – Change in Invoice Number Format (Effective 1st June 2025)

From 1st June 2025, the e-invoice portal will not differentiate between capital and small letters in invoice numbers.

That means:

abc123, ABC123, and Abc123 will all be treated as the same invoice number.

So if you use the same number with different letter cases, the system may show an error for duplicate invoice.

What you need to do:

Always enter invoice numbers in CAPITAL LETTERS across all systems to avoid issues in e-invoice generation.

This change is also in line with GSTR-1, which already works this way.

(Official advisory is attached)